SQL - 如何查找年初至今的金額？

Question

比方說，我有一個這樣叫小時表：

employee, payperiod, hours 
greg, 1/31/2010, 12 
greg, 1/31/2010, 15 
mark, 1/31/2010, 10 
mark, 1/31/2010, 11 
greg, 2/28/2010, 12 
greg, 2/28/2010, 15 
greg, 2/28/2010, 4 

我怎麼會發現，今年迄今爲止小時對於給定的員工和payperiod？

對於上面的例子我願意去：

employee, payperiod, hours_YTD 
greg, 1/31/2010, 27 
mark, 1/31/2010, 21 
greg, 2/28/2010, 58 
mark, 2/28/2010, 21 (this row is a nice to have, I can live without it if it's too tricky) 

到目前爲止，我已經試過，但總好像離：

select employee,payperiod,sum(hours) from hours h1 
join hours h2 on h2.payperiod<=h1.payperiod and h2.payperiod>=1/1/2010 
    and h1.employee=h2.employee 
group by h1.employee, h1.payperiod 

（我在SQL Server 2005）

Answer 1

這將在SELECT中使用子查詢來獲得運行總數。

致力於在28日獲得馬克。

select employee, 
     payperiod, 
     (SELECT sum ([hours]) FROM @hours f2 
      WHERE f2.payperiod <= f.payperiod and f2.employee=f.employee) as hh 

from @hours as f 
where YEAR(payperiod) = year(getdate()) --current year. 
group by employee, payperiod 
order by payperiod 

Answer 2

可能有更好的方法來獲得今年的第一個，但這似乎更容易一些。

Select 
    H.employee 
    , H.payperiod 
    , (Select Sum(H1.hours) 
    From hours as H1   
    Where H1.employee = H.employee 
     and H1.payperiod <= H.payperiod 
    ) as hours_YTD 
from hours as H 
where Year(H.payperiod) = Year(GetDate() 
    and H.payperiod <= GetDate() 
group by employee 
    , payperiod 

*最後一行將需要一個全新的宗教實踐的研究，除非它是表還是有一些你不告訴我們。